US5179726A - Automatic tuning method and apparatus of double conversion tuner - Google Patents

Automatic tuning method and apparatus of double conversion tuner Download PDF

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Publication number
US5179726A
US5179726A US07/619,302 US61930290A US5179726A US 5179726 A US5179726 A US 5179726A US 61930290 A US61930290 A US 61930290A US 5179726 A US5179726 A US 5179726A
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Prior art keywords
voltage
tuning
carrier wave
agc
signal
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Expired - Lifetime
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US07/619,302
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English (en)
Inventor
Tae-Hyung Moon
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Samsung Electro Mechanics Co Ltd
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Samsung Electro Mechanics Co Ltd
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Priority claimed from KR1019890017411A external-priority patent/KR910008131B1/ko
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Assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD., R.O. KOREA reassignment SAMSUNG ELECTRO-MECHANICS CO., LTD., R.O. KOREA ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: MOON, TAE-HYUNG
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J3/00—Continuous tuning
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H04N5/50—Tuning indicators; Automatic tuning control
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J1/00—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general
    • H03J1/0008—Details of adjusting, driving, indicating, or mechanical control arrangements for resonant circuits in general using a central processing unit, e.g. a microprocessor
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03J—TUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J5/00—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner
    • H03J5/02—Discontinuous tuning; Selecting predetermined frequencies; Selecting frequency bands with or without continuous tuning in one or more of the bands, e.g. push-button tuning, turret tuner with variable tuning element having a number of predetermined settings and adjustable to a desired one of these settings
    • H03J5/0245—Discontinuous tuning using an electrical variable impedance element, e.g. a voltage variable reactive diode, in which no corresponding analogue value either exists or is preset, i.e. the tuning information is only available in a digital form

Definitions

  • the present invention relates to an automatic tuning method and apparatus of a double conversion tuner, and more particularly, to an automatic tuning method and apparatus of a double conversion tuner in which tuning voltage corresponding to picture/sound carrier wave difference of a channel selected by double conversion tuner is transmitted to a voltage controlled oscillator to thereby be re-tuned so that the input filter inserting loss according to said picture/sound carrier wave is minimized.
  • tuning systems within television TV receivers use a number of tuners contained respectively with mixers in order to receive signals within a number of TV frequency bands. For example, a first tuner selects the channel within a VHF-TV frequency band (54 to 88 and 174 to 216 MHz) and a second tuner selects the channel within UHF-TV frequency band (470 to 890 MHz).
  • the tuning system for this should be added with a third tuner and mixed.
  • a double conversion tuning system for preventing complexity of a number of tuners and expensive cost is described for receiving broadcasting (air isolation) VHF-TV and UHF-TV signals as described in title of "high capacity TV” by D. L. arch on consumer electronic IEEE manual CE-24, 1st edition, February 1978, p 39-46.
  • simple and cheap tuning systems for receiveing VHF-TV, UHF-TV and CATV signal is required.
  • control device for generating tuning signal having a magnitude determined by frequency of selected channel; a first filter device for selecting an RF (radio frequency) signal corresponding to the channel selected from a first tuning band (low band) containing a lower frequency part of said first cable band (MB-CATV) and said first broadcasting band (L-VHF) in response to said tuning signal; a second filter device for selecting RF signals corresponding to the channel selected from a second tuning band (high band) containing an upper frequency part of said first cable band (MB-CATV), said second broadcasting band (H-VHF) and at least lower frequency part of said second cable band (SB-CATV) in response to said tuning signal, and a filter selecting device for operating said first filter device when the selected channel is at said first tuning band (low band) and for operating said second filter device when the selected channel is at said second tuning band (high band); and a multiple tuning system produces IF (
  • Control devices produce tuning signals having a magnitude determined by frequency of a selected channel.
  • the first filter selects an RF signal corresponding to the channel selected from the lower frequency part of the first cable band and the first tuning band including a first broadcasting band in response to the tuning signal.
  • the second filter selects an RF signal corresponding to the channel selected from the first cable band, the second broadcasting and the second tuning band in response to the tuning signal.
  • a selecting device operates the first filter when the selected signal is within the first tuning band, and operates the second filter when the selected channel is within the second tuning band.
  • a single conversion varactor tuner is utilized for utilizing broadcasting spectrum of television, and according to this single conversion varactor tuner, since the tuning voltages applied to varactor diodes of a voltage controlled oscillator (hereinafter, this will be abbreviated as VCO) and the radio frequency (hereinafter, called as RF) tuning circuit are the same, it is possible to tune said single conversion varactor tuner by one tuning voltage.
  • VCO voltage controlled oscillator
  • RF radio frequency
  • double conversion tuners should be utilized in order to utilize the broadcasting spectrum by using signals of more kinds than signals inputted to said single conversion varactor tuner and higher frequency signals, and according to this double conversion tuner, tuning voltages applied to varactor diodes of VCO and RF tuning circuit are respectively different.
  • the present invention is invented to solve the above-described conventional various problems, and it is an object of the present invention to provide an automatic tuning method and apparatus of a double conversion tuner for applying a tuning voltage to an RF tuning circuit which is different from the VCO tuning voltage applied to the double conversion tuner by utilizing a picture/sound carrier wave of an input channel inputted to the double conversion tuner.
  • the invention is characterized, in a tuning circuit of a tuner comprising a plurality of band pass filters for processing an RF signal inputted from an antenna input terminal and a high frequency amplifier as well as a matching circuit, a plurality of local oscillators for generating an oscillation signal with matching said inputted RF signal, and a plurality of mixers for outputting by mixing output signals of said matching circuit and local oscillator; by comprising a phase locked loop (PLL) circuit for controlling an oscillation signal of a local oscillator of said tuning circuit, video intermediate frequency producing circuit which receives an output signal of said tuning circuit whereby outputting an RF automatic gain control (AGC) signal and an IF automatic gain control signal, and automatic tuning means which receives two output signals from said video intermediate frequency producing circuit whereby controlling the band pass filter signal of said tuning circuit, and said automatic tuning section comprises a plurality of A/D converters for converting two analog signals from said video intermediate frequency producing circuit to a digital signal, ROM memory
  • FIGS. 1A and 1B are flow charts of a preferred embodiment of automatic tuning method according to the present invention.
  • FIGS. 2A-2F are graphs which illustrate a preferred embodiment of automatic tuning method according to FIGS. 1A and 1B, and
  • FIG. 3 is a block diagram of configuration applied with the method of the present invention.
  • FIG. 3 is a block diagram of system applied with automatic tuning method of double conversion tuner according to the present invention.
  • an RF input signal coming from an antenna 11 input stage is passed through a first band pass filter 12 and being sufficiently amplified at a first RF amplifier 13 and then passing through a matching circuit 14 to thereby be applied to a first mixer 15.
  • Said first mixer 15 mixes the input signal from said matching circuit 14 and an input signal from a first local oscillator 16 and then applying through a second band pass filter 17 to a second RF amplifier 18.
  • the first local oscillator 16 is controlled by PLL circuit 300 which is a control means for controlling VCO 100.
  • the signal applied to said second RF amplifier 18 is sufficiently amplified to thereby be mixed with the output signal of a second local oscillator 20 at a second mixer 19.
  • the signal mixed at said second mixer 19 is amplified again at third RF amplifier 21 to thereby be applied to video intermediate frequency producing circuit 30.
  • Said micom control device 40 is constructed in such a manner that ROM memory 44 and microprocessor 41 are connected to said A/D converters 42, 43.
  • said D/A converters 51, 52 convert the digital signal processed by said microprocessor 41 to analog signal to thereby be applied through comparator 50 for comparing the RF tuning voltage to said first band pass filter 12 whereby controlling the switching band.
  • the VCO tuning step 101 for tuning the VCO by utilizing PLL circuit 300 is passed through.
  • RF voltage tuning step 102 for tuning the RF voltage by a tuning voltage VT is read out by a program control contained within ROM memory element 44 of the microprocessor 41.
  • Said sweeping (a kind of scanning) process is as followings.
  • step 102 After said RF tuning step 102 is passed through, the AGC voltage controlled by a picture carrier wave VP and the maximum AGC voltage read out at ROM memory element 44 are compared at step 103.
  • PC is the picture carrier wave
  • SC is the sound carrier wave
  • the IF AGC voltage at step 104 is used, and when the maximum AGC voltage is larger than the AGC voltage tuned by said picture carrier wave, moving to step 105; tuning voltage VT is tuned such that the AGC voltage according to the picture carrier wave VP obtains maximum gain, and storing the AGC voltage V AGC (VP) according to the picture carrier wave at this moment to the memory element at step 106.
  • step 105 the waveform of FIG. 2B is appeared.
  • tuning voltage VT moves to a position same as voltage VP by picture carrier wave.
  • the tuning voltage VT is controlled so as the AGC voltage according to the sound carrier wave obtains maximum gain at step 108.
  • the reason for the increased F0 +4.5 MHz is for finding out the AGC voltage VS of the sound carrier wave, and said 4.5 MHz is a value SC-PC subtracting the picture carrier wave PC from the sound carrier wave SC.
  • tuning voltage VT is accorded with voltage VS.
  • AGC voltage VS, V AGC (VS) obtained by adjusting the tuning voltage VT at said step 108 are stored to memory element at step 109, and the VCO is adjusted for matching the oscillation frequency F0 according to RF signal at step 110.
  • VP- ⁇ VSP the AGC voltage V AGC (- ⁇ VSP) according to said tuning voltage (VP- ⁇ VSP) is stored to memory element at step 112.
  • the waveform of FIG. 2E is appeared.
  • the AGC voltage of the new picture/sound carrier wave of said step 113 is compared at step 114 and how much degree the absolute value (
  • the AGC voltage value VP' of said picture carrier wave is processed to the tuning voltage VT at step 123, and then it is terminated.
  • the present invention has the advantage that the input filter inserting loss corresponding to the picture/sound carrier wave by selecting the tuning voltage applied to the varactor diode of input RF tuning circuit corresponding to the channel which selected the respectively different tuning voltage of the double conversion tuner as a method according to the microprocessor.

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  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Superheterodyne Receivers (AREA)
  • Channel Selection Circuits, Automatic Tuning Circuits (AREA)
US07/619,302 1989-11-29 1990-11-28 Automatic tuning method and apparatus of double conversion tuner Expired - Lifetime US5179726A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR1019890017411A KR910008131B1 (ko) 1989-11-29 1989-11-29 더블 콘버젼(Double Conversion)튜너의 자동 동조방법
KR89-17411 1989-11-29
KR1019900018479A KR930007300B1 (ko) 1989-11-29 1990-11-15 더블 콘버젼(Double Conversion) 튜너의 자동 동조방법
KR90-18479 1990-11-15

Publications (1)

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US5179726A true US5179726A (en) 1993-01-12

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US07/619,302 Expired - Lifetime US5179726A (en) 1989-11-29 1990-11-28 Automatic tuning method and apparatus of double conversion tuner

Country Status (4)

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US (1) US5179726A (de)
JP (1) JPH0787346B2 (de)
KR (1) KR930007300B1 (de)
DE (1) DE4038110C2 (de)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996012351A1 (en) * 1994-10-17 1996-04-25 Scientific-Atlanta, Inc. Filter diplexer
US5752179A (en) * 1995-08-17 1998-05-12 Zenith Electronics Corporation Selective RF circuit with varactor tuned and switched bandpass filters
US6014547A (en) * 1997-04-28 2000-01-11 General Instrument Corporation System for enhancing the performance of a CATV settop terminal
US6161004A (en) * 1998-03-02 2000-12-12 Mentor Graphics Corporation Method and apparatus for rejecting image signals in a receiver
US6195539B1 (en) * 1998-03-02 2001-02-27 Mentor Graphics Corporation Method and apparatus for rejecting image signals in a receiver
US6564039B1 (en) * 2000-02-29 2003-05-13 Motorola, Inc. Frequency generation circuit and method of operating a tranceiver
US6697128B1 (en) * 1999-11-29 2004-02-24 Thomson Licensing S.A. Video frequency response
US20040125240A1 (en) * 2001-05-11 2004-07-01 Stikvoort Edward Ferdinand Integrated tuner circuit
US6975685B1 (en) * 2000-10-24 2005-12-13 Agere Systems Inc. Apparatus and method for multi-channel communications system
US20080081589A1 (en) * 2006-09-29 2008-04-03 Visteon Global Technologies, Inc. System for creating a programmable tuning voltage
US20090197553A1 (en) * 2005-12-01 2009-08-06 Thomson Licensing Method and Apparatus for Determining Frequency Offset in a Receiver
US9306531B2 (en) * 2014-03-06 2016-04-05 Linear Technology Corporation Exponential ROM table tuning using trim for frequency agile analog filters
US10277340B1 (en) * 2018-01-18 2019-04-30 Microchip Technology Incorporated Signal integrity diagnostics for communication channels

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4217190C2 (de) * 1992-05-23 2003-05-08 Grundig Ag Fernsehempfänger mit mikrocomputergesteuerter Verstärkungsregelung
DE4332161A1 (de) * 1993-09-22 1995-03-23 Thomson Brandt Gmbh Hochfrequenzempfänger
JP2006166009A (ja) * 2004-12-07 2006-06-22 Mitsubishi Electric Corp 受信装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3872387A (en) * 1972-09-29 1975-03-18 Zenith Radio Corp Frequency response modifier for fixed-tuned IF amplifiers
US4476583A (en) * 1983-02-28 1984-10-09 Rca Corporation Electronic tracking for tuners
US4499602A (en) * 1983-06-28 1985-02-12 Rca Corporation Double conversion tuner for broadcast and cable television channels
US4581643A (en) * 1983-07-25 1986-04-08 Rca Corporation Double conversion television tuner with frequency response control provisions
US4843639A (en) * 1988-03-17 1989-06-27 Beals Richard G Fully automatic garage door opener
US5012235A (en) * 1987-10-20 1991-04-30 Telefind Corporation Paging receiver with continuously tunable antenna and RF amplifier

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4408348A (en) * 1981-08-19 1983-10-04 Rca Corporation Multiband tuning system for a television receiver
US4402089A (en) * 1981-09-16 1983-08-30 Rca Corporation Television tuning system with electronic frequency adjustment apparatus
DE3347132C1 (de) * 1983-12-27 1985-07-04 Deutsche Thomson-Brandt Gmbh, 7730 Villingen-Schwenningen Automatisch arbeitendes Abgleichsystem fuer einen Tuner eines Fernsehempfangsgeraetes
US4780909A (en) * 1985-07-02 1988-10-25 Matsushita Electric Industrial Co. Ltd. Signal receiver having automatic frequency characteristic adjusting capability
JPS6373711A (ja) * 1986-09-16 1988-04-04 Pioneer Electronic Corp 周波数シンセサイザチユ−ナ
JPH01152811A (ja) * 1987-12-10 1989-06-15 Akai Electric Co Ltd 受信機の自動選局装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3872387A (en) * 1972-09-29 1975-03-18 Zenith Radio Corp Frequency response modifier for fixed-tuned IF amplifiers
US4476583A (en) * 1983-02-28 1984-10-09 Rca Corporation Electronic tracking for tuners
US4499602A (en) * 1983-06-28 1985-02-12 Rca Corporation Double conversion tuner for broadcast and cable television channels
US4581643A (en) * 1983-07-25 1986-04-08 Rca Corporation Double conversion television tuner with frequency response control provisions
US5012235A (en) * 1987-10-20 1991-04-30 Telefind Corporation Paging receiver with continuously tunable antenna and RF amplifier
US4843639A (en) * 1988-03-17 1989-06-27 Beals Richard G Fully automatic garage door opener

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1996012351A1 (en) * 1994-10-17 1996-04-25 Scientific-Atlanta, Inc. Filter diplexer
US5752179A (en) * 1995-08-17 1998-05-12 Zenith Electronics Corporation Selective RF circuit with varactor tuned and switched bandpass filters
US6014547A (en) * 1997-04-28 2000-01-11 General Instrument Corporation System for enhancing the performance of a CATV settop terminal
US6161004A (en) * 1998-03-02 2000-12-12 Mentor Graphics Corporation Method and apparatus for rejecting image signals in a receiver
US6195539B1 (en) * 1998-03-02 2001-02-27 Mentor Graphics Corporation Method and apparatus for rejecting image signals in a receiver
US6697128B1 (en) * 1999-11-29 2004-02-24 Thomson Licensing S.A. Video frequency response
US6564039B1 (en) * 2000-02-29 2003-05-13 Motorola, Inc. Frequency generation circuit and method of operating a tranceiver
US6975685B1 (en) * 2000-10-24 2005-12-13 Agere Systems Inc. Apparatus and method for multi-channel communications system
US20040125240A1 (en) * 2001-05-11 2004-07-01 Stikvoort Edward Ferdinand Integrated tuner circuit
US20090197553A1 (en) * 2005-12-01 2009-08-06 Thomson Licensing Method and Apparatus for Determining Frequency Offset in a Receiver
US20080081589A1 (en) * 2006-09-29 2008-04-03 Visteon Global Technologies, Inc. System for creating a programmable tuning voltage
US7660566B2 (en) 2006-09-29 2010-02-09 Visteon Global Technologies, Inc. System for creating a programmable tuning voltage
US9306531B2 (en) * 2014-03-06 2016-04-05 Linear Technology Corporation Exponential ROM table tuning using trim for frequency agile analog filters
US10277340B1 (en) * 2018-01-18 2019-04-30 Microchip Technology Incorporated Signal integrity diagnostics for communication channels

Also Published As

Publication number Publication date
JPH0787346B2 (ja) 1995-09-20
JPH0463012A (ja) 1992-02-28
KR930007300B1 (ko) 1993-08-04
DE4038110A1 (de) 1991-06-06
DE4038110C2 (de) 1998-12-03
KR910010843A (ko) 1991-06-29

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